Irrigation system with ET based seasonal watering adjustment

ABSTRACT

An ET based irrigation system includes a stand alone irrigation controller with a seasonal adjust feature and a stand alone weather station including at least one environmental sensor. The ET based irrigation system further includes a stand alone ET unit operatively connected to the irrigation controller and the weather station. The ET unit includes programming configured to calculate an estimated ET value using a signal from the environmental sensor and to automatically modify a watering schedule of the irrigation controller through the seasonal adjust feature based on the estimated ET value to thereby conserve water while maintaining plant health.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of similarly titled U.S. patentapplication Ser. No. 12/181,894 of Peter J. Woytowitz et al. filed Jul.29, 2008. This application is also a continuation-in-part of U.S. Ser.No. 13/011,301 of Porter et al., filed Jan. 21, 2011, which is acontinuation of U.S. Ser. No. 12/176,936 of Porter et al. filed Jul. 21,2008, now U.S. Pat. No. 7,877,168 granted Jan. 25, 2011. Said U.S. Ser.No. 12/176,936 is a continuation-in-part of U.S. Ser. No. 10/985,425 ofWoytowitz et al., filed Nov. 9, 2004, now U.S. Pat. No. 7,853,363granted Dec. 14, 2010, and a continuation-in-part of U.S. Ser. No.11/288,831 of Porter et al., filed Nov. 29, 2005, now U.S. Pat. No.7,412,303 granted Aug. 12, 2008. Priority is claimed off of the filingdates of each of the above-identified applications and patents, and theentire disclosures of each of the above-identified applications andpatents are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to residential and commercial irrigationsystems, and more particularly to irrigation controllers that useevapotranspiration (ET) data in calculating and executing wateringschedules.

BACKGROUND OF THE INVENTION

Electronic irrigation controllers have long been used on residential andcommercial sites to water turf and landscaping. They typically comprisea plastic housing that encloses circuitry including a processor thatexecutes a watering program. Watering schedules are typically manuallyentered or selected by a user with pushbutton and/or rotary controlswhile observing an LCD display. The processor turns a plurality ofsolenoid actuated valves ON and OFF with solid state switches inaccordance with the watering schedules that are carried out by thewatering program. The valves deliver water to sprinklers connected bysubterranean pipes.

There is presently a large demand for conventional irrigationcontrollers that are easy for users to set up in terms of entering andmodifying the watering schedules. One example is the Pro C® irrigationcontroller commercially available from Hunter Industries, Inc., theassignee of the subject application. The user simply enters the starttimes for a selected watering schedule, assigns a station to one or moreschedules, and sets each station to run a predetermined number ofminutes to meet the irrigation needs of the site. The problem withconventional irrigation controllers is that they are often set up toprovide the maximum amount of irrigation required for the hottest anddriest season, and then either left that way for the whole year, or insome cases the watering schedules are modified once or twice per year bythe user. The result is that large amounts of water are wasted. Water isa precious natural resource and there is an increasing need to conservethe same.

In one type of prior art irrigation controller the run cycles times forindividual stations can be increased or decreased by pushing “more” and“less” watering buttons. Another conventional irrigation controller ofthe type that is used in the commercial market typically includes aseasonal adjustment feature. This feature is typically a simple globaladjustment implemented by the user that adjusts the overall watering asa percentage of the originally scheduled cycle times. It is common forthe seasonal adjustment to vary between a range of about ten percent toabout one hundred and fifty percent of the scheduled watering. This isthe simplest and most common overall watering adjustment that users ofirrigation controllers can effectuate. Users can move the amount ofadjustment down to ten to thirty percent in the winter, depending ontheir local requirements. They may run the system at fifty percentduring the spring or fall seasons, and then at one hundred percent forthe summer. The ability to seasonally adjust up to one hundred and fiftypercent of the scheduled watering accommodates the occasional heat wavewhen turf and landscaping require significantly increased watering. Theseasonal adjustment feature does not produce the optimum wateringschedules because it does not take into consideration all of the ETfactors such as soil type, plant type, slope, temperature, humidity,solar radiation, wind speed, etc. Instead, the seasonal adjustmentfeature simply adjusts the watering schedules globally to run a longeror shorter period of time based on the existing watering program. Whenthe seasonal adjustment feature is re-set on a regular basis asubstantial amount of water is conserved and while still providingadequate irrigation in a variety of weather conditions. The problem isthat most users forget about the seasonal adjustment feature and do notre-set it on a regular basis, so a considerable amount of water is stillwasted, or turf and landscaping die.

In the past, irrigation controllers used with turf and landscaping haveused ET data to calculate watering schedules based on actual weatherconditions. Irrigation controllers that utilize ET data are quitecumbersome to set up and use, and require knowledge of horticulture thatis lacking with most end users. The typical ET based irrigationcontroller requires the user to enter the following types ofinformation: soil type, soil infiltration rates, sprinkler precipitationrate, plant type, slope percentage, root zone depth, and plant maturity.The controller then receives information, either directly or indirectly,from a weather station that monitors weather conditions such as: amountof rainfall, humidity, hours of available sunlight, amount of solarradiation, temperature, and wind speed. The typical ET based irrigationcontroller then automatically calculates an appropriate wateringschedule that may change daily based on the weather conditions andindividual plant requirements. These changes typically include thenumber of minutes each irrigation station operates, the number of timesit operates per day (cycles), and the number of days between watering.All of these factors are important in achieving the optimum wateringschedules for maximum water conservation while maintaining the health ofturf and landscaping.

While conventional ET based irrigation controllers help to conservewater and maintain plant health over a wide range of weather conditionsthey are complex and their set up is intimidating to many users. Theytypically require a locally mounted weather station having a complementof environmental sensors. Such locally mounted weather stations arecomplex, expensive and require frequent maintenance. Instead ofreceiving data from a locally mounted weather station, home owners andproperty owners can arrange for their ET based irrigation controllers toreceive weather data collected by a private company on a daily basis andtransmitted to the end user wirelessly, via phone lines or over anInternet connection. This reduces the user's up-front costs, andmaintenance challenges, but requires an ongoing subscription expense forthe life of the ET based irrigation controller. In addition, the usermust still have a substantial understanding of horticulture to set upthe ET based irrigation controller. For these reasons, most ET basedirrigation controllers are set up by irrigation professionals for a fee.These same irrigation professionals must be called back to the propertywhen changes need to be made, because the set up procedures are complexand not intuitive to most users. These challenges are limiting the saleand use of ET based irrigation controllers to a very small minority ofirrigation sites. This impairs water conservation efforts that wouldotherwise occur if ET based irrigation controllers were easier to set upand adjust.

SUMMARY OF THE INVENTION

The system of the present invention may take the form of stand aloneirrigation controller connected to a stand alone unit that isconnectable to a specially configured stand alone weather station.Alternatively, the system may take the form of a stand alone irrigationcontroller with a removable module that is connectable to a speciallyconfigured stand alone weather station. In yet another embodiment, thesystem may take the form of a stand alone irrigation controller with allthe components mounted in a single box-like housing that is connectableto a specially configured stand alone weather station.

In accordance with one aspect of the present invention an irrigationsystem includes a stand alone irrigation controller with a seasonaladjust feature and a specially configured stand alone weather stationincluding at least one environmental sensor. The irrigation systemfurther includes a stand alone unit operatively connected to theirrigation controller and the weather station. The stand alone unitincludes programming configured to calculate a seasonal adjustment valueusing a signal from the environmental sensor and to automatically modifya watering schedule of the irrigation controller through the seasonaladjust feature based on the calculated seasonal adjustment value tothereby conserve water while maintaining plant health.

In accordance with another aspect of the present invention an ET basedirrigation system includes an interface that enables a user to selectand/or enter a watering schedule and a memory for storing the wateringschedule. The system further includes at least one sensor for generatinga signal representative of an environmental condition. A processor isincluded in the system that is capable of calculating an estimated ETvalue based at least in part on the signal from the sensor. The systemfurther includes a program executable by the processor to enable theprocessor to generate commands for selectively turning a plurality ofvalves ON and OFF in accordance with the watering schedule. The programincludes a seasonal adjust feature that provides the capability forautomatically modifying the watering schedule based on the estimated ETvalue to thereby conserve water while maintaining plant health.

The present invention also provides a unique method of controlling aplurality of valves on an irrigation site using a calculated seasonaladjustment value. The method includes the step of calculating theseasonal adjustment value based in part on a signal from anenvironmental sensor. The method further includes the step ofautomatically modifying a watering schedule based on the calculatedseasonal adjustment value using a seasonal adjust algorithm to therebyconserve water while maintaining the health of plants on the irrigationsite. Optionally, the method of present invention may further includethe step of inputting an overall watering adjustment and automaticallymodifying the watering schedule through the seasonal adjust algorithmbased on an estimated ET value as increased or decreased by the inputtedoverall watering adjustment.

The present invention also provides a weather station for use with anirrigation controller. The weather station includes a housing thatsupports a rain sensor, a solar radiation sensor and a temperaturesensor. A micro-controller is also supported by the housing and isconnected to the sensors. A communications interface permitscommunications between the micro-controller and an irrigationcontroller. Firmware is executable by the micro-controller forperiodically sampling to the output of the sensors and providingrepresentative sensor data to the irrigation controller.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of an irrigation system inaccordance with an embodiment of the present invention.

FIG. 2 is a front elevation view of the stand alone irrigationcontroller of the system of FIG. 1 with its front door open to revealits removable face pack.

FIG. 3 is an enlarged perspective view of the back panel of the standalone irrigation controller of FIG. 2 illustrating one base module andone station module plugged into their respective receptacles in the backpanel.

FIG. 4 is a block diagram of the electronic portion of the stand aloneirrigation controller of FIG. 2.

FIG. 5 is a block diagram illustrating further details of the electronicportion of the stand alone irrigation controller of FIG. 2 that residesin the face pack of the controller.

FIG. 6 is a block diagram illustrating further details of the electronicportion of the stand alone irrigation controller of FIG. 2 that residesin the base module.

FIG. 7 is a block diagram illustrating further details of the electronicportion of the stand alone irrigation controller of FIG. 2 that residesin each of the station modules.

FIGS. 8A-8W are detailed flow diagrams illustrating the operation of thestand alone irrigation controller of FIG. 2.

FIG. 9 is a perspective view of the stand alone ET unit of the system ofFIG. 1.

FIG. 10 is a block diagram of the electronic portion of the stand aloneET unit of FIG. 9.

FIGS. 11A-11D are flow diagrams illustrating the operation of the standalone ET unit of FIG. 9.

FIG. 12A is an enlarged vertical cross-section of the stand aloneweather station of the system of FIG. 1.

FIG. 12B is a fragmentary perspective view illustrating the springbiased arm of the stand alone weather station of FIG. 12A.

FIG. 13 is a block diagram illustrating the electronic portion of thestand alone weather station of FIG. 12.

FIG. 14 is a flow diagram illustrating the operation of the stand aloneweather station of FIG. 12.

DETAILED DESCRIPTION

The entire disclosures of the following U.S. patents and U.S. patentapplications are hereby incorporated by reference: U.S. Pat. No.5,097,861 granted Mar. 24, 1992 of Hopkins et al. entitled IRRIGATIONMETHOD AND CONTROL SYSTEM; U.S. Pat. No. 5,444,611 granted Aug. 22, 1995of Peter J. Woytowitz, et al. entitled LAWN AND GARDEN IRRIGATIONCONTROLLER; U.S. Pat. No. 5,829,678 granted Nov. 3, 1998 of Richard E.Hunter et al. entitled SELF-CLEANING IRRIGATION REGULATOR VALVEAPPARATUS; U.S. Pat. No. 6,088,621 granted Jul. 11, 2000 also of PeterJ. Woytowitz et al. entitled PORTABLE APPARATUS FOR RAPID REPROGRAMMINGOF IRRIGATION CONTROLLERS; U.S. Pat. No. 6,721,630 granted Apr. 13, 2004also of Peter J. Woytowitz entitled EXPANDABLE IRRIGATION CONTROLLERWITH OPTIONAL HIGH-DENSITY STATION MODULE; U.S. Pat. No. 6,842,667granted Jan. 11, 2005 of Beutler et al. entitled POSITIVE STATION MODULELOCKING MECHANISM FOR EXPANDABLE IRRIGATION CONTROLLER; U.S. patentapplication Ser. No. 10/883,283 filed Jun. 30, 2004 also of Peter J.Woytowitz entitled HYBRID MODULAR/DECODER IRRIGATION CONTROLLER, nowU.S. Pat. No. 7,069,115 granted Jun. 27, 2007; pending U.S. patentapplication Ser. No. 10/985,425 filed Nov. 9, 2004 also of Peter J.Woytowitz et al. and entitled EVAPOTRANSPIRATION UNIT CONNECTABLE TOIRRIGATION CONTROLLER; pending U.S. patent application Ser. No.11/288,831 filed Nov. 29, 2005 of LaMonte D. Porter et al. and entitledEVAPOTRANSPIRATION UNIT FOR RE-PROGRAMMING AN IRRIGATION CONTROLLER;U.S. patent application Ser. No. 11/045,527 filed Jan. 28, 2005 also ofPeter J. Woytowitz entitled DISTRIBUTED ARCHITECTURE IRRIGATIONCONTROLLER, now U.S. Pat. No. 7,245,991 granted Jul. 17, 2007; U.S. Pat.No. 7,289,886 of Peter J. Woytowitz granted Oct. 30, 2007 entitledMODULAR IRRIGATION CONTROLLER WITH SEPARATE FIELD VALVE LINE WIRINGTERMINALS; U.S. Pat. No. 7,225,058 of LaMonte D. Porter granted May 29,2007 entitled MODULAR IRRIGATION CONTROLLER WITH INDIRECTLY POWEREDSTATION MODULES; pending U.S. patent application Ser. No. 11/458,551filed Jul. 19, 2006 of LaMonte D. Porter et al. entitled IRRIGATIONCONTROLLER WITH INTERCHANGEABLE CONTROL PANEL; and pending U.S. patentapplication Ser. No. 12/042,301 filed Mar. 4, 2008 of Peter J. Woytowitzet al. entitled IRRIGATION CONTROLLER WITH SELECTABLE WATERINGRESTRICTIONS. The aforementioned U.S. patents and applications are allassigned to Hunter Industries, Inc., the assignee of the subjectapplication.

The present invention addresses the hesitancy or inability of users tolearn the horticultural factors required to set up a conventional ETbased irrigation controller. The irrigation system of the presentinvention has a familiar manner of entering, selecting and modifying itswatering schedules, and either built-in or add-on capability toautomatically modify its watering schedules based on ET data in order toconserve water and effectively irrigate vegetation throughout the yearas weather conditions vary. The user friendly irrigation system of thepresent invention is capable of achieving, for example, eighty-fivepercent of the maximum amount of water that can theoretically beconserved on a given irrigation site, but is still able to be used bymost non-professionals. Therefore, a large percentage of users of theirrigation system of the present invention will have a much morebeneficial environmental impact than a near perfect solution provided bycomplex prior art ET based irrigation controllers that might at best beadopted a small percentage of users. Even within the small percentage ofusers that adopt the full ET device, many of them may not be set upcorrectly because of the complexities of ET, and may therefore operateinefficiently.

Referring to FIG. 1, in accordance with an embodiment of the presentinvention, an irrigation system 10 comprises a stand alone irrigationcontroller 12 connected via cable 14 to a stand alone ET unit 16 that isin turn connected via cable 18 to a stand alone weather station 20. Thecontroller 12 and ET unit 16 would typically be mounted in a garage orother protected location, although they can have a waterproofconstruction that allows them to be mounted out of doors. The weatherstation 20 is typically mounted on an exterior wall, gutter, post orfence near the garage. The cables 14 and 18 typically include copperwires so that power can be supplied to the ET 16 unit and the weatherstation 20 from the irrigation controller 12. Data and commands are senton other copper wires in the cables. Fiber optic cables can also beutilized for sending data and commands. The controller 12, ET unit 16and weather station 20 may exchange data and commands via wirelesscommunication links 22 and 24. A transformer 25 that plugs into astandard household 110 volt AC duplex outlet supplies twenty-four voltAC power to the stand alone irrigation controller 12. In its preferredform, the irrigation system 10 employs a hard wired communication link14 between the stand alone irrigation controller 12 and the stand aloneET unit 16 that are normally mounted adjacent one another, such as on agarage wall, and a wireless communication link 24 between the standalone ET unit 16 and the stand alone weather station 20.

Referring to FIG. 2, the stand alone irrigation controller 12 may be thePro-C modular irrigation controller commercially available from HunterIndustries, Inc. The irrigation controller 12 includes a wall-mountableplastic housing structure in the form of a generally box-shaped frontdoor 26 hinged along one vertical edge to a generally box-shaped backpanel 28 (FIG. 3). A generally rectangular face pack 30 (FIG. 2) isremovably mounted over the back panel 28 and is normally concealed bythe front door 26 when not being accessed for programming. The face pack30 has an interface in the form of a plurality of manually actuablecontrols including a rotary knob switch 31 and push button switches 32a-32 g as well as slide switch 34 which serves as a sensor by-passswitch. Watering schedules consisting of various run and cycle times canbe entered by the user by manipulating the rotary knob switch 31 andselected ones of the push button switches 32 a-32 g in conjunction withobserving numbers, words and/or graphic symbols indicated on a liquidcrystal display (LCD) 36. Push buttons 32 c and 32 d are used toincrease or decrease the seasonal adjust value. The watering schedulescan be a complicated set of run time and cycle algorithms, or a portionthereof, such as a simple five minute cycle for a single station.Alternatively, existing pre-programmed watering schedules can beselected, such as selected zones every other day. Any or sub-combinationof manually actuable input devices such as rotary switches, dials, pushbuttons, slide switches, rocker switches, toggle switches, membraneswitches, track balls, conventional screens, touch screens, etc. may beused to provide an interface that enables a user to select and/or entera watering schedule. Still another alternative involves uploadingwatering schedules through the SMART PORT (Trademark) feature of theirrigation controller 12, more details of which are set forth in theaforementioned U.S. Pat. No. 6,088,621.

The face pack 30 (FIG. 2) encloses and supports a printed circuit board(not illustrated) with a processor for executing and implementing astored watering program. An electrical connection is made between theface pack 30 and the components in the back panel 28 through adetachable ribbon cable including a plurality of conductors 38 a-g (FIG.4). The circuitry inside the face pack 30 can be powered by a battery toallow a person to remove the face pack 30, un-plug the ribbon cable, andwalk around the lawn, garden area or golf course while entering wateringschedules or altering pre-existing watering schedules.

A processor 40 (FIG. 5) is mounted on the printed circuit board insidethe face pack 30. A watering program stored in a memory 42 is executableby the processor 40 to enable the processor to generate commands forselectively turning a plurality of solenoid actuated irrigation valves(not illustrated) ON and OFF in accordance with the selected or enteredwatering schedule. An example of such an irrigation valve is disclosedin U.S. Pat. No. 5,996,608 granted Dec. 7, 1999 of Richard E. Hunter etal. entitled DIAPHRAGM VALVE WITH FILTER SCREEN AND MOVEABLE WIPERELEMENT, the entire disclosure of which is hereby incorporated byreference. Said patent is also assigned to Hunter Industries, Inc.Typically the solenoid actuated valves are mounted in subterraneanplastic boxes (not illustrated) on the irrigated site.

The processor 40 communicates with removable modules 44 and 46 a-c (FIG.3) each containing a circuit that includes a plurality of solid stateswitches, such as triacs. These switches turn twenty-four volt ACcurrent ON and OFF to open and close corresponding solenoid actuatedvalves via connected to dedicated field valve wires and a common returnline to screw terminals 48 on the modules 44 and 46 a-c.

In FIG. 3, the modules 44 and 46 a are shown installed in side-by-sidefashion in station module receptacles formed in the back panel 28. Themodule 44 serves as a base module that can turn a master valve ON andOFF in addition to a plurality of separate station valves. Each moduleincludes an outer generally rectangular plastic housing with a slot atits forward end. A small printed circuit board (not illustrated) withinthe module housing supports the station module circuit that includesconductive traces that lead to the screw terminals 48 and to V-shapedspring-type electrical contacts (not illustrated) that are accessiblevia the slot in the forward end of the module housing. These V-shapedelectrical contacts register with corresponding flat electrical contactson the underside of a relatively large printed circuit board 49 (FIG. 4)mounted inside the back panel 28 when the module 44 is slid into itscorresponding receptacle. The relatively large printed circuit board 49is referred to as a “back plane.” The base module 44 and station modules46 a-c and the back plane 49 are thus electrically and mechanicallyconnected in releasable fashion through a so-called “card edge”connection scheme when the base module 44 and station modules 46 a-c areinserted or plugged into their respective receptacles.

An elongate locking bar 50 (FIG. 3) can be manually slid up and down inFIG. 4 between locked and unlocked positions to secure and un-secure themodules 44 and 46 a-c after they have been fully inserted into theirrespective receptacles. Opposing raised projections 52 formed on thelocking bar 50 facilitate sliding the locking bar 50 with a thumb. Apointer 54 extends from one of the raised projections 52 and serves as aposition indicator that aligns with LOCKED and UNLOCKED indicia (notillustrated) molded into the upper surface of another plastic supportstructure 56 mounted inside back panel 28.

The receptacles for the modules such as 44 and 46 a-c are partiallydefined by vertical walls 58 (FIG. 3) formed on the back panel 28.Vertical walls 60 also formed on the back panel 28 to provide support tothe modules 44 and 46 a-c. An auxiliary terminal strip providesadditional screw terminals 62 for connecting remote sensors andaccessories. The term “receptacles” should be broadly construed asdefined in one or more of the patents and pending applicationsincorporated by reference above.

FIGS. 4 and 5 are block diagrams of the electronic portion of the standalone irrigation controller 12. The electronic components are mounted onprinted circuit boards contained within the face pack 30, back panel 28,base module 44 and station modules 46 a-c. The processor 40 (FIG. 4) ismounted on the printed circuit board inside the face pack 30 andexecutes the watering program stored in the memory 42. By way ofexample, the processor 40 may be a Samsung S3F8289 processor thatexecutes a program stored in the separate memory 42 which can be anindustry standard designation Serial EEPROM 93AA6A non-volatile memorydevice. Alternatively, the processor 40 and memory 42 may be provided inthe form of a micro-computer with on-chip memory. The manually actuablecontrols 31, 32 a-32 g and 34 and the LCD display 36 of the face pack 30are connected to the processor 40. The processor 40 sends drive signalsthrough buffer 64 and back plane 49 to the base module 44. By way ofexample the buffer 64 may be an industry standard designation 74HC125device. The processor 40 sends data signals to the modules 46 a-cthrough buffer 66. The buffer 66 may be an H-bridge buffer includingindustry standard 2N3904/3906 discrete bipolar transistors.

The processor 40 (FIG. 4) controls the base module 44 and the stationmodules 46 a-c in accordance with one or more watering schedules. Serialor multiplexed communication is enabled via the back plane 49 to thebase module 44 and to each of the output modules 46 a-c. Suitablesynchronous serial data and asynchronous serial data station modulecircuits are disclosed in the aforementioned U.S. Pat. No. 6,721,630.The location of each module in terms of which receptacle it is pluggedinto is sensed using resistors on the back plane 49 and a comparator 68(FIG. 5) which may be an industry standard LM393 device. The face pack30 receives twenty-four volt AC power from the transformer 25 throughthe back plane 49 and regulates the same via a power supply circuit 70(FIG. 5). The power supply circuit 70 includes a National SemiconductorLM7906 voltage regulator, a Microchip Technology MCP101-450 powersupervisor, and a Samsung KA431 voltage regulator. A lithium battery 72such as an industry standard CR2032 battery is included in the powersupply circuit 70 and provides backup power to the micro controller tomaintain the internal clock in the event of a power failure. The facepack ribbon cable 38 a-g (FIG. 4) that connects the face pack 30 and theback plane 49 can be disconnected, and a nine volt battery (FIG. 5) thensupplies power to the face pack 30. This allows a user to remove theface 30 pack from the back panel 28 and enter or modify wateringschedules as he or she walks around the irrigation site.

The modules 44 and 46 a-c have contacts 74 (FIG. 4) on the top sides oftheir outer plastic housings. When the modules are first plugged intotheir receptacles, only a communication path is established with theprocessor 40 via the back plane 49. At this time the locking bar 50(FIG. 3) is in its UNLOCKED position. Thereafter, when the locking baris slid to its LOCKED position finger-like contacts 76 (FIG. 4) on theunderside of the locking bar 50 register with the contacts 74 on thetops of the modules 44 and 46 a-c to supply twenty-four volt AC power tothe modules that is switched ON and OFF to the valves that are connectedto the modules. The finger-like contacts 76 are connected to a commonconductor 78 carried by the locking bar 50. When the locking bar 50 isslid to its LOCKED position projections and tabs that extend from thelocking bar 50 and the modules are aligned to prevent withdrawal of themodules. See the aforementioned U.S. Pat. No. 7,225,058 for furtherdetails.

FIG. 6 is a block diagram illustrating details of the electronic circuitof the base module 44. The base module circuit includes transistordrivers 80 and triacs 82 for switching the twenty-four volt AC signal ONand OFF to different solenoid actuated valves. By way of example, thetransistor drivers 80 may be industry standard 2N4403 transistors andthe triacs may be ST Microelectronics (Trademark) T410 triacs. Thetwenty-four volt AC signal is supplied to the triacs 82 via contact 74and line 83. The twenty-four volt AC signal from each of the triacs 82is routed through an inductor/MOV network 84 for surge suppression tofour field valve lines 86 a-d, each of which can be connected to acorresponding solenoid actuated valve. The valves are each connected toa valve common return line 88. The twenty-four volt AC signal is alsosupplied to a rectifier/filter circuit 90. The unregulated DC signalfrom the rectifier/filter circuit 90 is supplied to a NationalSemiconductor LM7905 voltage regulator 92 which supplies five volt DCpower to the face pack 30 via a conductor 38 c (FIG. 4) in the ribboncable.

FIG. 7 is a block diagram illustrating details of the electronic circuitin each of the station modules 46 a-c. The station module circuitincludes a microcontroller such as the Microchip (Trademark) PIC 12C508processor 94. The station module circuit further includes triacs 96 forswitching the twenty-four volt AC signal ON and OFF to three differentsolenoid actuated valves. The twenty-four volt AC signal is supplied tothe triacs 96 via contact 74 and line 98. The twenty-four volt AC signalfrom each of the triacs 94 is routed through an inductor/MOV network 98including Epcos Inc. S10K35 MOV's for surge suppression to three fieldvalve lines 100 a-c, each of which can be connected to a correspondingsolenoid actuated valve. The valves are each connected to the valvecommon return line 88. The twenty-four volt AC signal is also suppliedto a rectifier/filter circuit 90. The unregulated DC signal from therectifier/filter circuit 102 is supplied to a National SemiconductorLM7905 voltage regulator 104 which supplies five volt DC power to themicrocontroller through a conductor (not illustrated).

FIGS. 8A-8W are detailed flow diagrams illustrating the operation of thestand alone irrigation controller 12 of FIG. 2. Those skilled in the artof designing and programming irrigation controllers for residential andcommercial applications will readily understand the logical flow andalgorithms that permit the processor 40 to execute the watering programstored in the memory 42. This watering program enables the processor 40to generate commands for selectively turning the plurality of valves ONand OFF in accordance with the selected or entered watering schedules.The watering program includes a seasonal adjustment feature thatprovides the capability for automatically modifying the wateringschedules to thereby conserve water while maintaining plant health. Byactuating one of the push buttons 32 c or 32 d the user can increase ordecrease the run types for all stations by a selected scaling factor,such as ten percent, to account for seasonal variations in temperatureand rainfall.

Referring to FIG. 9, the stand alone ET unit 16 includes a rectangularouter plastic housing 106 enclosing a printed circuit board (notillustrated) which supports the electronic circuit of the ET unit 16that is illustrated in the block diagram of FIG. 10. A microcontroller108 such as a Microchip PIC18F65J90 processor executes firmwareprogramming stored in a memory 110 such as an industry standard 93AA66AEEPROM memory. The microcontroller 108 can receive DC power from alithium battery 112 such as an industry standard CR2032 battery, whichallows accurate time keeping in the event of a power failure. Insulatingstrip 113 (FIG. 9) must be manually pulled out to establish an operativeconnection of the battery 112. External power for the ET unit 16 issupplied from the transformer 25 (FIG. 1) via the cable 14. Thetwenty-four volt AC power from the transformer 25 is supplied to arectifier/filter circuit 114 (FIG. 10) which supplies twenty-four voltDC power to a power regulation circuit 116 which may be an STMicroelectronics L78M24CDT-TR regulator. Power from the power regulationcircuit 116 is fed to a microcontroller power regulator 118 which may bea Microchip MCP 1702T-25021/CB regulator. Power from the powerregulation circuit 116 is also fed to a wired or wireless sensorcommunications device 120 that may include, by way of example, anindustry standard MMBTA92 for the signal transmitter and an industrystandard LM393 comparator for the receiver.

The microcontroller 108 (FIG. 10) interfaces with the SmartPort(Trademark) connector of the irrigation controller 12 with a combinationinterface/optocoupler 122 which may be provided by an industry standard4N26S device. The microcontroller 108 interfaces with the weatherstation illustrated in FIG. 12. An LCD display 126 is mounted in thehousing 106. Three manually actuable controls in the form of pushbuttons 128 a-c (FIG. 9) are mounted in the housing 106 for enabling theuser to make selections when setting up and modifying the operation ofthe ET unit 16 in conjunction with information indicated on the display126 which is facilitated by column and row indicia 130 and 132,respectively, affixed to the housing 106 adjacent the horizontal andvertical margins of the display 126. Row indicia 132 include, from topto bottom, AM, PM, 24 hr, START and END which are printed, painted,molded or otherwise applied to the outer plastic housing such as by asticker. Column indicia 130 are illustrated diagrammatically as A-E inFIG. 9 due to space constraints in the drawing. A-E correspond,respectively, to TIME, TYPE, REGION, NO WATER and WATER+/−withassociated icons which are printed, painted, molded or otherwise appliedto the outer plastic housing 106 such as by a sticker.

FIGS. 11A-11D are flow diagrams illustrating the operation of the standalone ET unit 16. A watering schedule typically includes inputtedparameters such as start times, run times and days to water. The ET unit16 can automatically set the seasonal adjustment of the irrigationcontroller 12 to reduce watering time, or increase watering times,depending on the weather conditions at the time. The ET unit 16 utilizesactual ET data as its basis for making the modifications to the wateringschedules implemented by the irrigation controller 12. However, tosimplify the system and reduce the costs, some of the ET parameters maybe pre-programmed into the ET unit 16 as constants. These constants maybe selected from a group of geographical areas to approximatelyassimilate the local conditions and estimate a maximum ET value. Otherclimatic factors are monitored on a daily basis and are the variables.The variables may include one or more pieces of environmental data suchas temperature, humidity, solar radiation, wind, and rain. In thepreferred embodiment of the present invention, the measured variablesare temperature and solar radiation. The variables and any constants areused by the processor 108 to calculate an estimated ET value. Thisestimated ET value is then used by the ET unit 16 to automatically setthe seasonal adjustment feature of the irrigation controller 12. Theweather station 20 can also include a sensor that indicates a rainevent. A rain event does not effect calculation of an estimated ETvalue. However, it does shut of the irrigation during, and for a periodof time following, the rain event as a further conservation measure.

The user can modify the run and cycle times for individual stations inthe usual manner in the irrigation controller 12. As an example, if onestation is watering too much, but all of the other stations are wateringthe correct amount, the user can easily reduce the run time of thatparticular station and balance the system out. Then the ET unit 16continues modifying the watering schedules executed by the irrigationcontroller 12 on a global basis as a percentage of run time, based onthe calculated estimated ET value. Irrigation controllers can be used tocontrol landscape lighting and other non-irrigation devices such asdecorative water fountains. The controller 12 may have features in itsuch that the ET unit 16 only modifies the watering schedules of theirrigation controller 12.

One of the difficulties with conventional weather-based controllers isattributable to the difficulty of fine-tuning the weather data beingreceived. The environmental sensors may not always be able to be placedin an optimum location on the irrigation site. As an example, a solarradiation sensor may be placed in an area that receives late afternoonshade. This will result in the calculation of an abnormally lowestimated ET value. The entire irrigation site may receive too littlewater and the plant material may become stressed from too little waterif the watering schedules are based on an abnormally low estimated ET.If a conventional ET based irrigation controller receives input fromsuch an incorrectly located solar radiation sensor, the user can attemptto compensate by increasing the run times for each zone by modifyingprecipitation rates to compensate for the error. This is cumbersome andmakes it difficult and frustrating for the user to adjust a conventionalET based irrigation controller for optimum watering.

An advantage of the present invention is the ability to globally modifythe watering schedules of the stand alone irrigation controller 12 tocompensate for this type of condition. If at any time the user realizesthat the property is receiving too little water, the user can simplymanually change an overall watering adjustment feature. The overallwatering adjustment feature is implemented as a simple plus or minuscontrol via actuation of an assigned pair of the push buttons 128 a-c.This changes the reference point of the ET calculation either up ordown. After this adjustment is made, the ET adjustment executed by theET unit 16 references the new setting and then compensates for underwatering that would otherwise occur. Likewise, if the overall wateringis too much for the irrigation site, the user can simply adjust theoverall watering adjustment feature down and create a new lowerreference for the automatic ET based adjustments. The overall wateringadjustment feature makes it easy for the user to fine-tune the system tothe particular requirements of the irrigation site. The overall wateringadjustment feature can be indicated by showing “global adjustment,” or“more/less, water+/−,” or similar naming conventions.

The overall watering adjustment feature of the ET unit 16 directlyalters the station run times executed by the irrigation controller 12.This adjustment modifies the estimated maximum expected ET setting,which is a constant that is used in the calculating the seasonal adjustvalue. When the user makes overall watering adjustments by pressing plusor minus push buttons on the ET unit 16, this directly affects the ETvalue that is used to reset the seasonal adjustment in the hostcontroller 12. In calculating the estimated ET, the microcontroller 108in the ET unit 16 uses only select data points as variables (temperatureand solar radiation) and uses other data points that may consist ofpre-programmed constants, and/or data entered by the user that definessome one or more constants of the site. Estimated ET is calculated usingthe Penman-Monteith formula, taking into account geographical data forpeak estimated summer ET.

Another feature provided by the ET 16 is an automatic shut down featurefor irrigation that overrides any scheduled run times. There are severaltimes when this is important. A rain sensor in the weather station 20can send signals to the ET unit representing the occurrence of a rainevent. The ET unit 10 will then signal the irrigation controller 12 toshut down and suspend any watering, irregardless of any scheduledirrigation running or not running at the time. As another example,during a freeze or near freeze condition, irrigation may produce icethat can be dangerous to people walking or vehicles diving by. Manycities therefore require that irrigation be automatically turned off inthe event of a freeze condition. A temperature sensor in the weatherstation 20 can detect a freeze or near freeze condition and the ET unit16 will signal the irrigation controller 12 to shut down, regardless ofany scheduled irrigation running or not running at the time.

The automatic shut down feature of the ET unit 10 is also useful ingeographic areas where watering agencies and municipalities imposerestrictions that limit the times when irrigation can occur. The user isable to enter a no-water window into the ET unit 16, which consists ofthe times when irrigation is not allowed to take place. When a no-waterwindow is entered by the user, the ET unit 16 will signal the irrigationcontroller 12 to shut down, irregardless of any scheduled irrigationrunning or not running at the time. The ET unit 16 will then allow theirrigation controller 12 to return to its normal run mode after theselected no-water window time has elapsed. The irrigation controller 12may have sensor input terminals, as in the case of the Pro-C irrigationcontroller, which can be used to shut down all watering on receipt of ashut down command from the ET unit 16.

FIG. 12A is an enlarged vertical cross-section of an embodiment of thestand alone weather station 20 of the system of FIG. 1. The compact andinexpensive weather station 20 measures solar radiation, ambient airtemperature, and detects a rain event. The weather station 20 is aone-piece unit that readily attaches to an exterior side of a buildingstructure, a fence, or a rain gutter. The weather station 20 can be hardwired to the ET unit 16 via cable 18, or the communications between theweather station 20 and the ET unit 16 may take place via wirelesscommunications link 24. The basic construction of the weather station 20is similar to that disclosed in U.S. Pat. No. 6,570,109 granted May 27,2003 to Paul A. Klinefelter et al. entitled QUICK SHUT-OFF EXTENDEDRANGE HYDROSCOPIC RAIN SENSOR FOR IRRIGATION SYSTEMS, and U.S. Pat. No.6,977,351 granted Dec. 20, 2005 to Peter J. Woytowitz entitled MOISTUREABSORPTIVE RAIN SENSOR WITH SEALED POSITION SENSING ELEMENT FORIRRIGATION WATERING PROGRAM INTERRUPT, the entire disclosures of both ofwhich are incorporated herein by reference. Both of the aforementionedU.S. patents are assigned to Hunter Industries, Inc.

The weather station 20 (FIG. 12A) includes an outer injection moldedplastic housing 134 that encloses a pair of moisture absorbing membersin the form of a larger stack 136 of moisture absorbing hygroscopicdiscs and a smaller stack 138 of moisture absorbing hygroscopic discs.These discs are typically made of untreated wood fibers pressed togetherinto a material that resembles cardboard in appearance. One suitablecommercially available hygroscopic material is Kraft Press Board whichis made from cellulose pulp.

The stacks 136 and 138 (FIG. 12A) of hygroscopic discs are supported ona common pivot arm 140 for vertical reciprocal motion relative to avertical shaft 142 that extends through the arm 140. A coil spring 144surrounds the shaft 142 and normally pushes the stack 136 upwardlyagainst stop 146. A torsion spring 147 (FIG. 12B) associated with thepivot axis of the arm 140 lifts the arm 140 and the stack 138 upward toa fixed stop (not illustrated). When rain water enters the housing 134(FIG. 12A) via aperture 150 and funnel 152 the hygroscopic discs of thestacks 136 and 138 absorb water and swell, pushing the arm 140downwardly. A magnet 154 is mounted on one end of the arm 140. Astationary linear Hall effect sensor 156 mounted on a vertically mountedprinted circuit board 158 generates a signal representative of theposition of the magnet 154 that is proportional to the amount of rainwater that has entered the weather station 20. The Hall effect sensor156 may be provided by part number A1395SEHLT-T manufactured by Alegro.The small stack 138 absorbs water quickly via funnel 148 so that a rainevent will be quickly detected. The large stack 136 dries out slowly sothat the rain interrupt signal from the weather station 20 will not beterminated too quickly as the hydroscopic discs dry out. A solarradiation sensor 160 is mounted on one end of the printed circuit board158 and receives solar radiation through a clear plastic dome 162 snapfit over the uppermost part of the housing 134. The solar radiationsensor 160 may be an industry standard PDB-C131 photodiode with lowcurrent leakage.

FIG. 13 is a block diagram illustrating the electronic circuit of thestand alone weather station 20 that is mounted on the printed circuitboard 158. The solar radiation sensor 160 which may comprise a PDB-C131photodiode that is connected to a Microchip MCP6001T-I/LT transimpedanceamplifier 164 that is in turn connected to a Microchip PIC-16F684-I/SLmicrocontroller 166. A Microchip MCP9700T-E/LT temperature sensor 168with an A/D interface is also connected to the microcontroller 166. Themicrocontroller 166 also receives the output signal from the Hall effectsensor 156. The Hall effect sensor 156 may comprise a MicrochipA1395SEHLT-T Hall effect sensor and interface circuit. Thecommunications interface 170 between the microcontroller 166 and the ETunit 16 may be a hard wire interface, or more preferably, a wirelessinterface that may comprise a Microchip Technology RFPIC675 transmitterand a Maxim MAX1473 receiver. The transmitter sends signalsrepresentative of actual components of ET data across the irrigationsite to the ET unit 16. Power for the hard wired weather station 20 isderived from the communications link to the ET unit 16 and is fed to aninput conditioner 172 which feeds a Microchip MCP1702T-3002E/CB powerregulator 174. The power regulator 174 supplies three volt DC power tothe microcontroller 166. Power for a wireless weather station issupplied by a dedicated battery (not illustrated) installed within theweather station.

FIG. 14 is a flow diagram illustrating the operation of the stand aloneweather station 20 of FIG. 12. Firmware executed by the microcontroller166 allows the weather station 20 to perform the logical operationsillustrated in the flow diagram. These include periodic sampling of theoutputs from the solar radiation sensor 162, temperature sensor 168 andHall effect sensor 156, averaging readings, and responding to requestsfor sensor data that are periodically transmitted by the ET unit 16.

In conclusion, the ET unit 16 of the present invention utilizes thewatering program set up procedures that the users are already accustomedto. Start times, station run times, and days-to-water are manuallyentered into the irrigation controller 12. The user also selects fromone of a group of geographical regions in the ET unit 16. The ET unit 16then automatically takes over setting of the seasonal adjustment featureof the irrigation controller 12 on a regular basis. Instead of a userchanging that feature several times per year, the ET unit 16 sets thatseasonal adjustment daily depending on current weather conditionsgathered on site. Furthermore, the ET unit 16 shuts down any scheduledwatering by the irrigation controller 12 in response to a rain event ora freeze event, and when there is a scheduled no-water window. Costsavings are achieved since only a small number of the weather parametersneed to be measured. These variables are then used with pre-programmedconstants to calculate an estimated ET value. This approach allows forcost savings since the stand alone weather station 20 need not have morethan a solar radiation sensor, a temperature sensor and a rain sensor.

The present invention also provides a unique method of controlling aplurality of valves on an irrigation site. The method includes the stepsof selecting and/or creating a watering schedule, storing the wateringschedule and generating a signal representative of an environmentalcondition on an irrigation site. The method also includes the steps ofcalculating an estimated ET value based at least in part on the signaland selectively turning a plurality of valves located on the irrigationsite ON and OFF in accordance with the watering schedule. Importantly,the method includes the further step of automatically modifying thewatering schedule based on the estimated ET value using a seasonaladjust algorithm to thereby conserve water while maintaining the healthof plants on the irrigation site. Optionally, the method of presentinvention may further include the step of inputting an overall wateringadjustment and automatically modifying the watering schedule through theseasonal adjust algorithm based on the estimated ET value as increasedor decreased by the inputted overall watering adjustment.

While an embodiment of an irrigation system comprising a stand alone ETunit connected to stand alone irrigation controller and linked to aseparate stand alone weather station has been described in detail,persons skilled in the art will appreciate that the present inventioncan be modified in arrangement and detail. The features andfunctionality described could be provided by combining the irrigationcontroller and the ET unit into a single integrated unit in which case asingle microcontroller would replace the microcontrollers 40 and 108.Alternatively, the ET unit could be packaged in an ET module designedfor removable insertion into a receptacle in a stand alone irrigationcontroller. Therefore, the protection afforded the subject inventionshould only be limited in accordance with the scope of the followingclaims.

What is claimed is:
 1. An irrigation system, comprising: a stand aloneirrigation controller comprising: a control panel including a displayand a plurality of user inputs that enable a user to enter a wateringschedule including a run time, and to manually adjust a percentageadjustment value of a percentage adjustment feature; a computerprocessor operatively connected to the control panel; a memory connectedto the computer processor; a plurality of switches operatively connectedto the computer processor for turning a power signal ON and OFF to aplurality of valves that deliver water to a plurality of sprinklers; andprogramming stored in the memory to accept input from the user via theplurality of user inputs to implement the watering schedule, whereinduring said run time, the computer processor operates ones of theplurality of switches to turn the power signal ON to one or more of theplurality of valves thereby delivering the water to ones of thesprinklers to irrigate an irrigation site, the programming furtheraccepting input from the user via the plurality of user inputs toimplement said percentage adjustment feature to increase or decrease therun time of the watering schedule by the percentage adjustment value; astand alone weather station different from the stand alone irrigationcontroller including at least one environmental sensor; and a standalone evapotranspiration (ET) control unit different from andoperatively in communication with the stand alone irrigation controllerand the stand alone weather station, the stand alone ET control unitinstalled on the irrigation site and comprising a memory storingprogramming that calculates an ET value using a signal from the at leastone environmental sensor and communicates an ET adjustment valueresponsive to the ET value to the computer processor of the stand aloneirrigation controller to automatically increase or decrease saidpercentage adjustment value of the percentage adjustment, saidpercentage adjustment feature configured to change said wateringschedule by said percentage adjustment value.
 2. The system of claim 1wherein the programming of the stand alone ET control unit provides thecapability to enter a no-water window that automatically overrides thewatering schedule.
 3. The system of claim 1 wherein the programming ofthe stand alone ET control unit provides the capability to automaticallyshut down any watering otherwise scheduled based on a detected event. 4.The system of claim 1 wherein the stand alone weather station includes asolar radiation sensor, a temperature sensor, and a rain sensor, and theET value is calculated using signals from the solar radiation sensor andthe temperature sensor, and a plurality of pre-programmed constants. 5.The system of claim 1 wherein the stand alone ET control unit isoperatively connected to the stand alone weather station through awireless communications link.
 6. The system of claim 1 wherein the standalone ET control unit is configured to receive power from the standalone irrigation controller.
 7. The system of claim 1 wherein the standalone weather station includes a solar radiation sensor, a temperaturesensor, and a rain sensor, and the ET value is calculated by the standalone ET control unit using signals from the solar radiation sensor, thetemperature sensor, and a plurality of pre-programmed constants, whereindata entered by a user determines at least one pre-programmed constant.8. The system of claim 1 wherein the stand alone ET control unitcommunicates the ET adjustment value to the stand alone irrigationcontroller through a data port of the stand alone irrigation controller.9. The system of claim 1 wherein the stand alone ET control unitincludes manually actuable controls configured to enable the user toinput an overall watering adjustment by selectively increasing anddecreasing an estimated maximum ET setting, the memory storingprogramming that calculates the ET value using the signal from the atleast one environmental sensor and a calculation reference point basedon the estimated maximum ET setting entered by the user.
 10. Theirrigation system of claim 1 wherein the percentage adjustment featurecomprises a seasonal adjustment feature.
 11. The irrigation system ofclaim 1 further comprising an ET housing housing said stand alone ETcontrol unit.
 12. The irrigation system of claim 11 wherein said EThousing comprises a handheld housing.
 13. The irrigation system of claim11 wherein said ET housing is mountable to a housing of said stand aloneirrigation controller.
 14. The irrigation system of claim 1 wherein theET adjustment value comprises a percentage.
 15. An evapotranspiration(ET) based irrigation system, comprising: an interface including adisplay and a plurality of user inputs that enables a user to enter awatering schedule including a run time and to manually adjust apercentage adjustment value of a percentage adjustment feature; acomputer processor operatively connected to the interface; a memoryconnected to the computer processor to store the watering schedule; aplurality of switches operatively connected to the computer processorand configured to turn a power signal ON and OFF to a plurality ofvalves that deliver water to a plurality of sprinklers; at least oneenvironmental sensor configured to generate a signal representative ofan environmental condition the computer processor configured tocalculate an ET value based at least in part on the signal from the atleast one environmental sensor and determine an ET adjustment valueresponsive to the ET value; and programming stored in the memory toaccept input from the user via the plurality of user inputs to implementthe watering schedule, wherein during said run time, the computerprocessor operates ones of the plurality of switches to turn the powersignal ON to one or more of the plurality of valves thereby deliveringthe water to ones of the sprinklers to irrigate an irrigation site, theprogramming further accepting input from the user via the user inputs toimplement said percentage adjustment feature to increase or decrease therun time of the watering schedule by the percentage adjustment value,the programming automatically increasing or decreasing said percentageadjustment value of the percentage adjustment feature based on the ETadjustment value, said percentage adjustment feature configured tochange said run time of said watering schedule by said percentageadjustment value.
 16. The system of claim 15 wherein the programmingcalculates the ET value based on the signal from the environmentalsensor and a plurality of pre-programmed constants, wherein data enteredby the user determines at least one pre-programmed constant of a givensite.
 17. The system of claim 15 wherein the programming calculates theET value based on the signal from the environmental sensor and aplurality of pre-programmed constants.
 18. The system of claim 15wherein the interface includes manually actuable switches forselectively increasing and decreasing an estimated maximum ET setting,the computer processor calculating the ET value using the signal fromthe at least one environmental sensor and the estimated maximum ETsetting entered by the user.
 19. The ET based irrigation system of claim15 wherein the percentage adjustment feature comprises a seasonaladjustment feature.
 20. The ET based irrigation system of claim 15wherein the ET adjustment value comprises a percentage.
 21. A method ofcontrolling a plurality of valves on an irrigation site, the methodcomprising: accepting inputs from a user that enable the user to enter awatering schedule including a run time, and to manually adjust apercentage adjustment value of a percentage adjustment feature; storingthe watering schedule; receiving a signal representative of a currentenvironmental condition on an irrigation site; calculating anevapotranspiration (ET) value based at least in part on the signal;determining an ET adjustment value responsive to the ET value;selectively turning a power signal ON to a plurality of valves thatdeliver water to a plurality of sprinklers located on the irrigationsite in accordance with the watering schedule; implementing saidpercentage adjustment feature to increase or decrease the run time ofthe watering schedule by the percentage adjustment value; andautomatically increasing or decreasing said percentage adjustment valueof the percentage adjustment feature based on the ET adjustment value,said percentage adjustment feature configured to change said wateringschedule by said percentage adjustment value.
 22. The method of claim 21wherein the ET value is calculated based on the signal and a pluralityof predetermined constants.
 23. The method of claim 21 wherein theestimated ET value is calculated based on signals generated by a solarradiation sensor and a temperature sensor located on the irrigationsite, and a plurality of predetermined constants.
 24. The method ofclaim 23 wherein data based on the signals generated by the solarradiation sensor and the temperature sensor is transmitted wirelesslyacross the irrigation site.
 25. The method of claim 21 wherein the ETvalue is calculated based on the signal and a plurality of predeterminedconstants, wherein data entered by the user determines at least onepredetermined constant.
 26. The method of claim 21 wherein the estimatedET value is calculated based on data generated by a solar radiationsensor and a temperature sensor located on the irrigation site, and aplurality of predetermined constants, wherein data entered by the userdetermines at least one predetermined constant.
 27. The method of claim21 wherein the percentage adjustment feature comprises a seasonaladjustment feature.
 28. The method of claim 21 wherein the ET adjustmentvalue comprises a percentage.